Publication detail

Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

STRATIL, L. HADRABA, H. BURŠÍK, J. DLOUHÝ, I.

Czech title

Srovnání mikrostukturních vlastností a nárazového chování mezi odlišnými plechy z oceli Eurofer97 a vliv izotermického žíhání

English title

Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing

Type

journal article - other

Language

en

Original abstract

The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 degree C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative elektron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M23C6 and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the tDBTT of thicker plate was on +10 degree C higher than for 14 mm plate for which reached -60 degree C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight karbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in tDBTT about +5 degree C, which was most likely caused by recrystallization of subgrains.

Czech abstract

Příspěvek se zabývá zkoumáním mikrostruktury a lomového chování plechů z oceli Eurofer97 tloušťky 14 a 25 mm v dodaném stavu a ve stavu po dlouhodobém žíhání (550 stupňů C-5000 h). Detailní mikrostrukturní studie byly provedeny s využitím světelné, elektronové a kvantitativní elektronové mikroskopie. Mechanické vlastnosti byly hodnoceny pomocí Charpy zkoušky rázem v ohybu a měřením tvrdosti a na lomových plochách byl provedena fraktografická analýza v makro a mikro měřítku. Mikrostruktura oceli Eurofer97 je tvořena popuštěným martenzitem s precipitáty typu M23C6 a MX. Plech tloušťky 14 mm vykazoval více homogenní a jemnozrnnou strukturu oproti 25 mm plechu. Hrubší mikrostruktura 25 mm plechu byla příčinou jeho vyšší tDBTT o +10 stup ňů C ve srovnání s plechem tloušťky 14 mm, pro který dosáhla -60 stupňů C. Po aplikovaném izotermickém žíhání byly pozorovány jemné mikrostrukuturní změny na úrovni subzrn sestávající se z jejich částečné rekrystalizace a jemného hrubnutí karbidů. Izotermické žíhání způsobilo zřejmý posun tDBTT o asi +5 stupňů C pravděpodobně způsobený vlivem částečné rekrystalizace subzrn.

English abstract

The microstructure and fracture properties of the Eurofer97 steel plates of thickness 14 mm and 25 mm were investigated in as-received state and in state after long-term thermal ageing (550 degree C/5000 h). Detailed microstructure studies were carried out by means of optical light, electron and quantitative elektron microscopy. Mechanical properties were evaluated by means of Charpy impact testing and hardness testing and fracture surfaces were fractographically analysed in macro and microscales. The microstructure of the Eurofer97 consisted of tempered martensite with M23C6 and MX precipitates. Microstructure of 14 mm plate was more homogenous and fine grained than 25 mm plate. Due to different microstructure the tDBTT of thicker plate was on +10 degree C higher than for 14 mm plate for which reached -60 degree C. Slight microstructural changes on the level of subgrain consisting of their partial recrystallization and slight karbide coarsening were observed after applied ageing. The isothermal ageing caused evident shift in tDBTT about +5 degree C, which was most likely caused by recrystallization of subgrains.

Keywords in Czech

Eurofer97, tranzitní teplota, nárazové chování, hrubnutí karbidů

Keywords in English

Eurofer97, DBTT, impact behaviour, carbide coarsening

RIV year

2011

Released

30.09.2011

ISSN

0022-3115

Volume

416

Number

3

Pages from–to

311–317

Pages count

7

BIBTEX


@article{BUT75997,
  author="Luděk {Stratil} and Hynek {Hadraba} and Jiří {Buršík} and Ivo {Dlouhý},
  title="Comparison of microstructural properties and Charpy impact behaviour between different plates of the Eurofer97 steel and effect of isothermal ageing",
  year="2011",
  volume="416",
  number="3",
  month="September",
  pages="311--317",
  issn="0022-3115"
}